I think we have to be skeptical of that number based on the evidence that is out there from the investigation. To wit:
It isn't outrageous for someone to claim 1,000 hours in a year; I know numerous airline guys who hit this number somewhat regularly. Definitely unusual for a non-military, non-airline guy to be getting that amount of hours, but I wouldn't find it impossible to believe.
It is, however, not possible that he flew 5,200 hours in one year. This would mean he was logging 14 hours of flight time per day, every day, for 365 days. And since he reported only 200 hours of time during the "last 6 months" of that year...well, apparently Mac was logging augmented crew time while he was sleeping.
But, even that first number has to be taken in perspective of other evidence, like:
So, if the B-17 was flying under 300 hours per year total, even if you make the assumption that Mac was flying every single one of those hours (which we know he wasn't - I personally know people who flew 909 during that timeframe, and not with Mac in the seat), where were the other 700-ish hours per year coming from? This would require him to fly *double* the amount of hours he was theoretically getting in the B-17 in some other aircraft on the tour.
Remember, Mac was not a professional pilot at any point during his career and Collings was the only flying he was doing.
The evidence here shows that there was some amount of "Parker P-51" time going on here. How much? Tough to say...but it could be a substantial amount based on the self-reporting from the FAA medicals. He had to understand that the hour report to the FAA on your medical is an official attestation of your flight experience.
I admit, I bought into the Mac mystique too. The way he was spoken about by other pilots, as well as the way he spoke and carried himself, I'd have thought he was some old 'Nam vet, or old fire-bomber pilot, or retired airline guy. I was surprised to learn in this report that he'd only had his multiengine rating since 1999, and that he'd never actually had a professional flying career.
The data here, as well as his actions during the emergency, give me many many questions about the authenticity of basically anything said about his credentials or experience.